One of the secrets of managing successfully on solar power
is to choose efficient appliances
. The aim is to enjoy all the creature comforts without the hassle associated with a generator
kettles have introduced two new technologies that help:
1.They can be selected to stop at a lower temperature than 100°C. By stopping just before boiling, the energy wasted converting a liquid into a gas is saved. As a side benefit this also releases much less water
vapour reducing condensation
and mould problems in the boat
2. Vacuum insulated kettles are available.
I have used a variable temperature electric
kettle for some time, but recently upgraded to newer model with both variable temperature and thermal insulation
. The main benefit of the latter is that by retaining heat inside the kettle and in any excess hot water
that is not immediately used, there are energy savings on subsequent reboils. This energy saving will depend on the time between reboils and the quantity of water left so quantifing this energy saving in a representative way is difficult.
There are also some energy savings on the first boil. This occurs because less energy is lost
via convention while the kettle is heating
up. I expected these savings to be quite small, but decided to find out.
I won’t bore you with the experimental details, but I tried to control all the variables by using a measured quantity of water and checking the water temperature before and after heating
. Results were averaged. Both kettles were set to stop just below boiling (90-95°C).
The non insulated kettle required on average 114 Whrs (this would be about 9.2 Ahrs for a 12v system) to raise 1L (around 1 quart) from around 20°C (68°F) to just below boiling.
The thermally insulated kettle required 101 Whrs (this would be about (8.1 Ahrs), but actually had a higher finishing temperature (the water was closer to boiling) by around 5°C.
After taking the higher finishing temperature into account the vacuum insulated kettle was around 30% more efficient. This is is an impressive result, especially as the savings in subsequent reboils will be much greater.